This Program Project is designed to coordinate the research in rheumatic diseases within the Division of Clinical Immunology and Rheumatology. The laboratories devoted to biochemistry, immunopathology, immunophysiology and collagen structure will be coordinated in order to put into perspective new information as it relates directly to understanding disease processes. Specific areas of study include: 1) Studies on immunoglobulins relative to the way in which they interact with complement as well as the mechanism by which damage to target organs occurs. The interrelationships of our studies clearly delineates the way in which macromolecular structure is important in understanding the processes by which damage to target organs take place. 2) Model systems of inflammation that parallel complement and immunoglobulin studies in man. 3) Changes in parameters of immunopathology in clinical disease. 4) Expansion of our studies into the new area of immunogenetics, cell surface antigens and membrane structure. In addition, these investigations form the framework around which all of our clinical research and patient care center. Questions rising from specific problems of patient care at the bedside are finally analyzed through the various approaches included in this Coordinated Study in Rheumatic Diseases.